Develop Reference

ListView of images not working

I'm trying to customize ListView to show a list of images so i wrote the following code but unfortunately its not working.
layout/menu.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent" android:background="#drawable/menu_bg">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/name"
android:layout_gravity="center"/>
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/menu_list"
android:layout_gravity="center"
android:layout_marginTop="60sp"></ListView>
</LinearLayout>
layout/menu_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/item"/>
</LinearLayout>
Menu.java
public class Menu extends Activity{
private int[] items = {R.drawable.res_opt, R.drawable.new_game_opt, R.drawable.score_opt, R.drawable.exit_opt};
ListView list;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu);
list = (ListView) findViewById(R.id.menu_list);
list.setAdapter(new MenuAdapter(Menu.this, items));
}
}
MenuAdapter.java
public class MenuAdapter extends ArrayAdapter{
private int[] items;
private Context context;
public MenuAdapter(Context context, int[] items) {
super(context, R.layout.menu_item);
this.context = context;
this.items = items;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
//make sure we have a view to work with
View itemView = convertView;
if(itemView == null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE );
itemView = inflater.inflate(R.layout.menu_item,null, true);
}
//Find the object to work with
int id = items[position];
//Fill the view
ImageView item = (ImageView) itemView.findViewById(R.id.item);
item.setImageResource(id);
return itemView;
}
}

Add view holder class to your code, as its incomplete.
public class ViewHolder{
public ImageView iv;
}
Now, your code will look like this:
ViewHolder mViewHolder = new ViewHolder();
if(itemView == null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE );
itemView = inflater.inflate(R.layout.menu_item,null, null);
mViewHolder.iv = (ImageView) itemView.findViewById(R.id.item);
itemView.setTag(mViewHolder);
}else{
mViewHolder = (ViewHolder) itemView.getTag();
}
//Find the object to work with
int id = items[position];
//Fill the view
mViewHolder.iv.setImageResource(id);
Also, you have missed adding size for you ListView adapter.
Hope, this could help you.

You need to use another super constuctor of ArrayAdapter.
public class MenuAdapter extends ArrayAdapter<Integer>{
private Integer[] items;
private Context context;
public MenuAdapter(Context context, Integer[] items) {
super(context, R.layout.menu_item, items);
this.context = context;
this.items = items;
}
Edited
Also fix this line
itemView = inflater.inflate(R.layout.menu_item,parent, false);

Android text and bitmap in menu items

In my app, I am creating a dynamic list of items using
shopsNameList = new ArrayList<String>();
// Create The Adapter
ArrayAdapter<String> arrayAdapter =
new ArrayAdapter<String>(ShopsListActivity.this, android.R.layout.simple_list_item_1, shopsNameList);
I would like to have a text and an image in each element of the list, not a simple text.
I defined a listviewitem.xml layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:id="#+id/listitemimage"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:src="#raw/shop" />
<TextView
android:id="#+id/textview"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="Test" />
</LinearLayout>
and tried
ArrayAdapter<String> arrayAdapter =
new ArrayAdapter<String>(ShopsListActivity.this, R.layout.listviewitem, shopsNameList);
but my app crashes when I enter the list.
I am inside an activity creted with
super.onCreate(saveInstanceState);
setContentView(R.layout.shopslist);
// Get the reference of ListView
ListView shopsList=(ListView)findViewById(R.id.listShops);
shopsNameList = new ArrayList<String>();
shopElements = new ArrayList<ShopElement>();

You need to create custom adapter for your ListView:
public class CustomAdapter extends ArrayAdapter<String>{
Context context;
public CustomAdapter(Context context, List< String > objects)
{
super( context, R.layout.listviewitem, objects );
this.context = context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ShopListHolder holder = null;
if(convertView == null)
{
LayoutInflater inflater = LayoutInflater.from( context );
convertView = inflater.inflate(R.layout.listviewitem, parent, false);
holder = new ShopListHolder();
holder.imgIcon = (ImageView)convertView.findViewById(R.id.listitemimage);
holder.txtTitle = (TextView)convertView.findViewById(R.id.textview);
convertView.setTag(holder);
}
else
{
holder = (ShopListHolder )convertView.getTag();
}
holder.txtTitle.setText(getItem( position ));
return convertView;
}
class ShopListHolder
{
ImageView imgIcon;
TextView txtTitle;
}
}

Can't find ViewByID in Custom Adapter

I created my own custom adapter that extends Array Adapter:
public class AdapterGeoArea extends ArrayAdapter<GeoArea>{
private Context _context;
private int resource;
private ArrayList<GeoArea> _myGeoArea;
public AdapterGeoArea(Context context, ArrayList<GeoArea> myGeoArea) {
super(context, 0, myGeoArea);
_context = context;
_myGeoArea = myGeoArea;
}
public int getCount() {
return _myGeoArea.size();
}
public View getView(int position, View convertView, ViewGroup parent) {
LinearLayout GeoAreaView;
if (convertView == null) {
GeoAreaView = new LinearLayout(_context);
LayoutInflater li = LayoutInflater.from(_context);
convertView = li.inflate(R.layout.layout_geo_areas, null);
}
else {
GeoAreaView = (LinearLayout) convertView;
}
GeoArea curGeoArea = _myGeoArea.get(position);
TextView name = (TextView) GeoAreaView.findViewById(R.id.txtGeoAreaName);
name.setText(curGeoArea.name);
return convertView;
}
static class ViewHolder {
TextView name;
RelativeLayout childContainer;
}
#Override
public Filter getFilter() {
return null;
}
}
And here is how I am using it in my main:
public class ActivityGeoAreas extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_geo_areas);
GeoArea.searchTerm = "Bar & Grill";
GeoArea torontoArea = new GeoArea("cityOfToronto");
ArrayList<GeoArea> testList = new ArrayList<GeoArea>();
testList.add(torontoArea);
AdapterGeoArea adapter = new AdapterGeoArea(this, testList);
ListView lv = (ListView) findViewById(R.id.textGeoArea);
lv.setAdapter(adapter);
}
}
Everything seem to be fine except for this line:
TextView name = (TextView) GeoAreaView.findViewById(R.id.textGeoArea);
And here is how I defined my layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".ActivityGeoAreas" >
<TextView
android:id="#+id/textGeoArea"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Choose Area"
android:textAppearance="?android:attr/textAppearanceLarge" />
<LinearLayout
android:id="#+id/LinearLayoutGeoAreas"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textGeoArea"
android:layout_below="#+id/textGeoArea"
android:orientation="vertical" >
<ListView
android:id="#+id/listViewGeoArea"
android:layout_width="wrap_content"
android:layout_height="match_parent" >
</ListView>
</LinearLayout>
</RelativeLayout>
It simply can't find the TextView textGeoArea and this line become null, what am I doing wrong?

Change this
TextView name = (TextView) GeoAreaView.findViewById(R.id.txtGeoAreaName);
to
TextView name = (TextView) convertView.findViewById(R.id.txtGeoAreaName);
I guess you have got confused.
Move textview to a new layout list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/textGeoArea"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="14dp"
android:text="Choose Area"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
Now change your getView as below
LayoutInflater inflater;
public AdapterGeoArea(Context context, ArrayList<GeoArea> myGeoArea) {
super(context, 0, myGeoArea);
_context = context;
_myGeoArea = myGeoArea;
inflater = LayoutInflater.from(context); // initialize inflater
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_row,parent,false);
holder = new ViewHolder();
holder.tv = (TextView)convertView.findViewById(R.id.textGeoArea);
holder.setTag(convertView);
}
else {
holder = (ViewHolder) convertView.getTag();
}
GeoArea curGeoArea = _myGeoArea.get(position);
holder.tv.setText(curGeoArea.name);
return convertView;
}
static class ViewHolder // use a view holder for smooth scrolling an performance
{
TextView tv;
}

On the first pass, GeoAreaView is a childless LinearLayout since you just created it. convertView is the View initialized your layout which holds the TextView. So you need to use that to find the TextView.
TextView name = (TextView) convertView.findViewById(R.id.txtGeoAreaName);
I see you have a ViewHolder but you don't appear to be using it. You may want to take a little time and go through a good tutorial on using ListView.
This guy usually seems to have good tutorials

Can't find TextView in recursive custom Listview adapter

I created this class called GeoArea, which is suppose to store "Geographical Area" that have children Geographical Areas, this is fairly strait foward:
public class GeoArea {
public String id;
public String name;
public List<GeoArea> subGeoAreas;
public GeoArea parentGeoArea;
public GeoArea(String id) {
this.id = id;
name = id;
subGeoAreas = new LinkedList<GeoArea>();
}
#Override
public String toString() {
return name;
}
}
I have created the following Layout to render it on Android, the idea here is to for each GeoArea to recursively render it self and then it's children GeoArea in a listView:
//layout_geo_area.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/txtGeoAreaName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:gravity="left"
android:text="Geo Area Name"
android:textAppearance="?android:attr/textAppearanceLarge" />
<ListView
android:id="#+id/listViewChildGeoAreas"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/txtGeoAreaName"
android:gravity="left" >
</ListView>
</RelativeLayout>
This is my adapter I created for GeoArea to be displayed in a listView:
public class AdapterGeoArea extends ArrayAdapter<GeoArea>{
private ArrayList<GeoArea> _myGeoArea;
private Context _myContext;
LayoutInflater _inflater;
public AdapterGeoArea(Context context, ArrayList<GeoArea> myGeoArea) {
super(context, 0, myGeoArea);
_myGeoArea = myGeoArea;
_inflater = LayoutInflater.from(context);
_myContext = context;
}
public int getCount() {
return _myGeoArea.size();
}
public View getView(int position, View convertView, ViewGroup parent) {
GeoAreaLayoutHolder holder;
if (convertView == null) {
convertView = _inflater.inflate(R.layout.layout_geo_area,parent,false);
holder = new GeoAreaLayoutHolder();
holder.txtGeoAreaName = (TextView)convertView.findViewById(R.id.txtGeoAreaName);
holder.txtGeoAreaName.setTag(convertView);
holder.listViewChildGeoAreas = (ListView)convertView.findViewById(R.id.listViewChildGeoAreas);
holder.listViewChildGeoAreas.setTag(convertView);
} else {
holder = (GeoAreaLayoutHolder) convertView.getTag();
}
GeoArea curGeoArea = _myGeoArea.get(position);
holder.txtGeoAreaName.setText(curGeoArea.name);
if(curGeoArea.subGeoAreas.size()>0){
ArrayList<GeoArea> testList = new ArrayList<GeoArea>();
AdapterGeoArea adapter = new AdapterGeoArea(_myContext, testList);
for(GeoArea childGeoArea:curGeoArea.subGeoAreas){
testList.add(childGeoArea);
}
holder.listViewChildGeoAreas.setAdapter(adapter);
}
return convertView;
}
static class GeoAreaLayoutHolder {
public TextView txtGeoAreaName;
public ListView listViewChildGeoAreas;
}
}
And here is my Activity that I am using to set it all up:
public class ActivityGeoAreas extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_geo_area);
GeoArea.searchTerm = "Bar & Grill";
GeoArea torontoArea = new GeoArea("cityOfToronto");
ArrayList<GeoArea> testList = new ArrayList<GeoArea>();
testList.add(torontoArea);
AdapterGeoArea adapter = new AdapterGeoArea(this, testList);
ListView lv = (ListView) findViewById(R.id.listViewChildGeoAreas);
lv.setAdapter(adapter);
}
}
When I try to run it, I get the error nullPointerException on the line:
holder.txtGeoAreaName.setText(curGeoArea.name);
What am I doing wrong?

You may want to check ExpandableListView may suit your needs better
http://developer.android.com/reference/android/widget/ExpandableListView.html
An example # http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/
Continuing from my previous answer to your question ( i though that solved your problem)
To display just name in your listview
list_row.xml // this is the layout with textview to be inflated in getView.
Each row will have textview
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/textGeoArea"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="14dp"
android:text="Choose Area"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
layout_geo_area.xml // with only listview no textview
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ListView
android:id="#+id/listViewChildGeoAreas"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:gravity="left" >
</ListView>
</RelativeLayout>
Now your adapter class
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.list_row,parent,false);
// inflate list_row.xml with textview
holder = new ViewHolder();
holder.tv = (TextView)convertView.findViewById(R.id.textGeoArea);
holder.setTag(convertView);
}
else {
holder = (ViewHolder) convertView.getTag();
}
GeoArea curGeoArea = _myGeoArea.get(position);
holder.tv.setText(curGeoArea.name);
return convertView;
}
static class ViewHolder // use a view holder for smooth scrolling an performance
{
TextView tv;
}
You have a custom adapter.
public class AdapterGeoArea extends ArrayAdapter<GeoArea>{
Now you set the adapter to listview like below
AdapterGeoArea adapter = new AdapterGeoArea(this, testList);
ListView lv = (ListView) findViewById(R.id.listViewChildGeoAreas);
lv.setAdapter(adapter);
So why do you need the below. remove these
if(curGeoArea.subGeoAreas.size()>0){
ArrayList<GeoArea> testList = new ArrayList<GeoArea>();
AdapterGeoArea adapter = new AdapterGeoArea(_myContext, testList);
for(GeoArea childGeoArea:curGeoArea.subGeoAreas){
testList.add(childGeoArea);
}
holder.listViewChildGeoAreas.setAdapter(adapter);

Properly use SpinnerAdapter

I'm trying to get my spinneradapter working. I get no error's but
the spinner remains empty. I have read multiple tutorials but they aren't seem to work
very well. I'm trying to turn every row in a specifik color, that's why I need the adapter.
This is my code:
public class spinnerAdapter extends ArrayAdapter<String> implements
SpinnerAdapter {
Context context;
ArrayList<String> dateArray;
public spinnerAdapter(Context context, ArrayList<String>dateArray) {
super(context, R.layout.ruilen2_spinner);
this.context = context;
this.dateArray = dateArray;
}
static class ViewHolder {
public TextView textView;
public TextView textView2;
}
#Override
public View getDropDownView(int position, View view, ViewGroup parent) {
View rowView = view;
final ViewHolder holder;
if (rowView == null) {
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
rowView = vi.inflate(R.layout.ruilen2_spinner, null);
holder = new ViewHolder();
holder.textView = (TextView)rowView.findViewById(R.id.spinnerdate);
//holder.textView2 = (TextView)rowView.findViewById(R.id.spinnerworkplace);
rowView.setTag(holder);
}
else{
holder = (ViewHolder) rowView.getTag();
}
holder.textView.setText(dateArray.get(position));
return super.getDropDownView(
position, rowView, parent);
}
}
Here's the code snippet where I call the class:
s.setAdapter(new spinnerAdapter(getParent(),namen));
And last but not least the XML:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:background="#color/white"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="#+id/spinnerdate" android:textColor="#color/black"></TextView>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="#+id/spinnerworkplace" android:textColor="#color/black"></TextView>
</LinearLayout>

If it is displaying but is empty then you might not be creating your dateArray properly. Did you check to make sure namen in s.setAdapter(new spinnerAdapter(getParent(),namen)); has anything in it?